This invention relates to a method of recognizing speech and to a device therefor.
Broadly speaking, a speech recognition device can be divided structurally into (1) a calculating unit for calculating characteristic parameters of the speech and (2) a decision unit for matching the characteristic parameters with standard parameters and for recognizing the speech on the basis thereof. As the characteristic parameters of the speech, there have been employed a linear prediction coefficient, a partial auto-correlation coefficient or a filter bank output. When any of these parameters are used, the speech pattern is generally expressed as a time series of parameters of several orders. When an 8-order autocorrelation coefficient, which is sampled every 10 milliseconds, is to be considered, for example, 800 parameters are necessary to express a speech of one second duration so that there is a great increase in processing required for comparative operation with parameters of the standard patterns necessary for recognition. In addition, a large capacity memory is needed to store the standard patterns. Accordingly, it is necessary to obtain effective characteristic parameters capable of representing the speech patterns with as high a level of fidelity as possible.